/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS 180-1
 * Version 2.2 Copyright Paul Johnston 2000 - 2009.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance   */

/*
 * These are the functions you'll usually want to call
 * They take string arguments and return either hex or base-64 encoded strings
 */
function hex_sha1(s) {
    return rstr2hex(rstr_sha1(str2rstr_utf8(s)));
}

function b64_sha1(s) {
    return rstr2b64(rstr_sha1(str2rstr_utf8(s)));
}

function any_sha1(s, e) {
    return rstr2any(rstr_sha1(str2rstr_utf8(s)), e);
}

function hex_hmac_sha1(k, d) {
    return rstr2hex(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d)));
}

function b64_hmac_sha1(k, d) {
    return rstr2b64(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d)));
}

function any_hmac_sha1(k, d, e) {
    return rstr2any(rstr_hmac_sha1(str2rstr_utf8(k), str2rstr_utf8(d)), e);
}

/*
 * Perform a simple self-test to see if the VM is working
 */
function sha1_vm_test() {
    return hex_sha1("abc").toLowerCase() == "a9993e364706816aba3e25717850c26c9cd0d89d";
}

/*
 * Calculate the SHA1 of a raw string
 */
function rstr_sha1(s) {
    return binb2rstr(binb_sha1(rstr2binb(s), s.length * 8));
}

/*
 * Calculate the HMAC-SHA1 of a key and some data (raw strings)
 */
function rstr_hmac_sha1(key, data) {
    var bkey = rstr2binb(key);
    if (bkey.length > 16) bkey = binb_sha1(bkey, key.length * 8);

    var ipad = Array(16), opad = Array(16);
    for (var i = 0; i < 16; i++) {
        ipad[i] = bkey[i] ^ 0x36363636;
        opad[i] = bkey[i] ^ 0x5C5C5C5C;
    }

    var hash = binb_sha1(ipad.concat(rstr2binb(data)), 512 + data.length * 8);
    return binb2rstr(binb_sha1(opad.concat(hash), 512 + 160));
}

/*
 * Convert a raw string to a hex string
 */
function rstr2hex(input) {
    try {
        hexcase
    } catch (e) {
        hexcase = 0;
    }
    var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
    var output = "";
    var x;
    for (var i = 0; i < input.length; i++) {
        x = input.charCodeAt(i);
        output += hex_tab.charAt((x >>> 4) & 0x0F)
            + hex_tab.charAt(x & 0x0F);
    }
    return output;
}

/*
 * Convert a raw string to a base-64 string
 */
function rstr2b64(input) {
    try {
        b64pad
    } catch (e) {
        b64pad = '';
    }
    var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    var output = "";
    var len = input.length;
    for (var i = 0; i < len; i += 3) {
        var triplet = (input.charCodeAt(i) << 16)
            | (i + 1 < len ? input.charCodeAt(i + 1) << 8 : 0)
            | (i + 2 < len ? input.charCodeAt(i + 2) : 0);
        for (var j = 0; j < 4; j++) {
            if (i * 8 + j * 6 > input.length * 8) output += b64pad;
            else output += tab.charAt((triplet >>> 6 * (3 - j)) & 0x3F);
        }
    }
    return output;
}

/*
 * Convert a raw string to an arbitrary string encoding
 */
function rstr2any(input, encoding) {
    var divisor = encoding.length;
    var remainders = Array();
    var i, q, x, quotient;

    /* Convert to an array of 16-bit big-endian values, forming the dividend */
    var dividend = Array(Math.ceil(input.length / 2));
    for (i = 0; i < dividend.length; i++) {
        dividend[i] = (input.charCodeAt(i * 2) << 8) | input.charCodeAt(i * 2 + 1);
    }

    /*
     * Repeatedly perform a long division. The binary array forms the dividend,
     * the length of the encoding is the divisor. Once computed, the quotient
     * forms the dividend for the next step. We stop when the dividend is zero.
     * All remainders are stored for later use.
     */
    while (dividend.length > 0) {
        quotient = Array();
        x = 0;
        for (i = 0; i < dividend.length; i++) {
            x = (x << 16) + dividend[i];
            q = Math.floor(x / divisor);
            x -= q * divisor;
            if (quotient.length > 0 || q > 0)
                quotient[quotient.length] = q;
        }
        remainders[remainders.length] = x;
        dividend = quotient;
    }

    /* Convert the remainders to the output string */
    var output = "";
    for (i = remainders.length - 1; i >= 0; i--)
        output += encoding.charAt(remainders[i]);

    /* Append leading zero equivalents */
    var full_length = Math.ceil(input.length * 8 /
        (Math.log(encoding.length) / Math.log(2)))
    for (i = output.length; i < full_length; i++)
        output = encoding[0] + output;

    return output;
}

/*
 * Encode a string as utf-8.
 * For efficiency, this assumes the input is valid utf-16.
 */
function str2rstr_utf8(input) {
    var output = "";
    var i = -1;
    var x, y;

    while (++i < input.length) {
        /* Decode utf-16 surrogate pairs */
        x = input.charCodeAt(i);
        y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
        if (0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF) {
            x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
            i++;
        }

        /* Encode output as utf-8 */
        if (x <= 0x7F)
            output += String.fromCharCode(x);
        else if (x <= 0x7FF)
            output += String.fromCharCode(0xC0 | ((x >>> 6) & 0x1F),
                0x80 | (x & 0x3F));
        else if (x <= 0xFFFF)
            output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
                0x80 | ((x >>> 6) & 0x3F),
                0x80 | (x & 0x3F));
        else if (x <= 0x1FFFFF)
            output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
                0x80 | ((x >>> 12) & 0x3F),
                0x80 | ((x >>> 6) & 0x3F),
                0x80 | (x & 0x3F));
    }
    return output;
}

/*
 * Encode a string as utf-16
 */
function str2rstr_utf16le(input) {
    var output = "";
    for (var i = 0; i < input.length; i++)
        output += String.fromCharCode(input.charCodeAt(i) & 0xFF,
            (input.charCodeAt(i) >>> 8) & 0xFF);
    return output;
}

function str2rstr_utf16be(input) {
    var output = "";
    for (var i = 0; i < input.length; i++)
        output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,
            input.charCodeAt(i) & 0xFF);
    return output;
}

/*
 * Convert a raw string to an array of big-endian words
 * Characters >255 have their high-byte silently ignored.
 */
function rstr2binb(input) {
    var output = Array(input.length >> 2);
    for (var i = 0; i < output.length; i++)
        output[i] = 0;
    for (var i = 0; i < input.length * 8; i += 8)
        output[i >> 5] |= (input.charCodeAt(i / 8) & 0xFF) << (24 - i % 32);
    return output;
}

/*
 * Convert an array of big-endian words to a string
 */
function binb2rstr(input) {
    var output = "";
    for (var i = 0; i < input.length * 32; i += 8)
        output += String.fromCharCode((input[i >> 5] >>> (24 - i % 32)) & 0xFF);
    return output;
}

/*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
function binb_sha1(x, len) {
    /* append padding */
    x[len >> 5] |= 0x80 << (24 - len % 32);
    x[((len + 64 >> 9) << 4) + 15] = len;

    var w = Array(80);
    var a = 1732584193;
    var b = -271733879;
    var c = -1732584194;
    var d = 271733878;
    var e = -1009589776;

    for (var i = 0; i < x.length; i += 16) {
        var olda = a;
        var oldb = b;
        var oldc = c;
        var oldd = d;
        var olde = e;

        for (var j = 0; j < 80; j++) {
            if (j < 16) w[j] = x[i + j];
            else w[j] = bit_rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
            var t = safe_add(safe_add(bit_rol(a, 5), sha1_ft(j, b, c, d)),
                safe_add(safe_add(e, w[j]), sha1_kt(j)));
            e = d;
            d = c;
            c = bit_rol(b, 30);
            b = a;
            a = t;
        }

        a = safe_add(a, olda);
        b = safe_add(b, oldb);
        c = safe_add(c, oldc);
        d = safe_add(d, oldd);
        e = safe_add(e, olde);
    }
    return Array(a, b, c, d, e);

}

/*
 * Perform the appropriate triplet combination function for the current
 * iteration
 */
function sha1_ft(t, b, c, d) {
    if (t < 20) return (b & c) | ((~b) & d);
    if (t < 40) return b ^ c ^ d;
    if (t < 60) return (b & c) | (b & d) | (c & d);
    return b ^ c ^ d;
}

/*
 * Determine the appropriate additive constant for the current iteration
 */
function sha1_kt(t) {
    return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :
        (t < 60) ? -1894007588 : -899497514;
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(x, y) {
    var lsw = (x & 0xFFFF) + (y & 0xFFFF);
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function bit_rol(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
}
